Bags for pizza and similar food products have been in use for several years and some are insulated to keep the food product warm. However, even when insulated, these bags generally fail to keep the food product from getting cold before it is delivered. What is needed is a thermal bag which is well insulated and has a built-in heater for maintaining the contents of the bag at the desired temperature during the actual delivery process.
In accordance with the present invention, the thermal bag has top and bottom panels and is closed at the rear end and at the sides, but has an opening at the front for the insertion and removal of a food product. The bag preferably is insulated and has a built-in heating device with a thermostat to maintain the bag at the desired temperature.
Preferably, the thermostat is placed in the center of the top panel for most effective use. The heating device can be plugged into the cigarette lighter of the delivery vehicle so that the bag remains heated up to the point of actual delivery. Thus, the pizza or other food product in the bag will remain hot no matter what weather conditions, traffic conditions or delivery distance prevail. A thermofuse is preferably employed to prevent overheating as might occur as a result of failure of the thermostat.
Preferably, the bag is made of soft, flexible, multi-layer material having inner and outer sheets of heavy duty Nylon, for example, and with the heating device provided with heating elements in both the top and bottom panels. The heating device is an integral part of the bag and will not interfere with the insertion and/or removal of the food product.
The material of the bag itself is preferably of such an extremely flexible nature that is may be turned inside out for cleaning the inside of the bag.
One object of this invention is to provide a thermal bag having the foregoing features and capabilities.
Another object is to provide a thermal bag which is of simple construction, is rugged and durable in use, and is capable of being inexpensively manufactured.
Other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.